# IRelay

> Stores confirmed Merkle roots and signing policies.

> For the complete documentation index, see [llms.txt](/llms.txt). Markdown versions of documentation pages are available by appending `.md` to the page URL.

Source: https://dev.flare.network/network/fsp/solidity-reference/IRelay

Stores confirmed Merkle roots and signing policies.

Sourced from `IRelay.sol` on [GitHub](https://github.com/flare-foundation/flare-smart-contracts-v2/blob/main/contracts/userInterfaces/IRelay.sol).

## Functions[​](#functions "Direct link to Functions")

### feeCollectionAddress[​](#feecollectionaddress "Direct link to feeCollectionAddress")

Returns fee collection address.

```
function feeCollectionAddress() external view returns (    address payable);
```

### getRandomNumber[​](#getrandomnumber "Direct link to getRandomNumber")

Returns the current random number, its timestamp and the flag indicating if it is secure.

```
function getRandomNumber() external view returns (    uint256 _randomNumber,    bool _isSecureRandom,    uint256 _randomTimestamp);
```

#### Returns[​](#returns "Direct link to Returns")

-   `_randomNumber`: The current random number.
-   `_isSecureRandom`: The flag indicating if the random number is secure.
-   `_randomTimestamp`: The timestamp of the random number.

### getRandomNumberHistorical[​](#getrandomnumberhistorical "Direct link to getRandomNumberHistorical")

Returns the historical random number for a given \_votingRoundId, its timestamp and the flag indicating if it is secure. If no finalization in the \_votingRoundId, the function reverts.

```
function getRandomNumberHistorical(    uint256 _votingRoundId) external view returns (    uint256 _randomNumber,    bool _isSecureRandom,    uint256 _randomTimestamp);
```

#### Parameters[​](#parameters "Direct link to Parameters")

-   `_votingRoundId`: The voting round id.

#### Returns[​](#returns-1 "Direct link to Returns")

-   `_randomNumber`: The current random number.
-   `_isSecureRandom`: The flag indicating if the random number is secure.
-   `_randomTimestamp`: The timestamp of the random number.

### getVotingRoundId[​](#getvotingroundid "Direct link to getVotingRoundId")

Returns the voting round id for given timestamp.

```
function getVotingRoundId(    uint256 _timestamp) external view returns (    uint256 _votingRoundId);
```

#### Parameters[​](#parameters-1 "Direct link to Parameters")

-   `_timestamp`: The timestamp.

#### Returns[​](#returns-2 "Direct link to Returns")

-   `_votingRoundId`: The voting round id.

### governanceFeeSetup[​](#governancefeesetup "Direct link to governanceFeeSetup")

Checks the relay message for sufficient weight of signatures of the hash of the \_config data. If the check is successful, the relay contract is configured with the new \_config data, which in particular means that fee configurations are updated. Otherwise the function reverts.

```
function governanceFeeSetup(    bytes _relayMessage,    struct IRelay.RelayGovernanceConfig _config) external;
```

#### Parameters[​](#parameters-2 "Direct link to Parameters")

-   `_relayMessage`: The relay message.
-   `_config`: The new relay configuration.

### isFinalized[​](#isfinalized "Direct link to isFinalized")

Returns true if there is finalization for a given protocol id and voting round id.

```
function isFinalized(    uint256 _protocolId,    uint256 _votingRoundId) external view returns (    bool);
```

#### Parameters[​](#parameters-3 "Direct link to Parameters")

-   `_protocolId`: The protocol id.
-   `_votingRoundId`: The voting round id.

### lastInitializedRewardEpochData[​](#lastinitializedrewardepochdata "Direct link to lastInitializedRewardEpochData")

Returns last initialized reward epoch data.

```
function lastInitializedRewardEpochData() external view returns (    uint32 _lastInitializedRewardEpoch,    uint32 _startingVotingRoundIdForLastInitializedRewardEpoch);
```

#### Returns[​](#returns-3 "Direct link to Returns")

-   `_lastInitializedRewardEpoch`: Last initialized reward epoch.
-   `_startingVotingRoundIdForLastInitializedRewardEpoch`: Starting voting round id for it.

### merkleRoots[​](#merkleroots "Direct link to merkleRoots")

Returns the Merkle root for given protocol id and voting round id. The function is reverted if signingPolicySetter is set, hence on all deployments where the contract is used as a pure relay.

```
function merkleRoots(    uint256 _protocolId,    uint256 _votingRoundId) external view returns (    bytes32 _merkleRoot);
```

#### Parameters[​](#parameters-4 "Direct link to Parameters")

-   `_protocolId`: The protocol id.
-   `_votingRoundId`: The voting round id.

#### Returns[​](#returns-4 "Direct link to Returns")

-   `_merkleRoot`: The Merkle root.

### protocolFeeInWei[​](#protocolfeeinwei "Direct link to protocolFeeInWei")

Returns fee in wei for one verification of a given protocol id.

```
function protocolFeeInWei(    uint256 _protocolId) external view returns (    uint256);
```

#### Parameters[​](#parameters-5 "Direct link to Parameters")

-   `_protocolId`: The protocol id.

### relay[​](#relay "Direct link to relay")

Finalization function for new signing policies and protocol messages. It can be used as finalization contract on Flare chain or as relay contract on other EVM chain. Can be called in two modes. It expects calldata that is parsed in a custom manner. Hence the transaction calls should assemble relevant calldata in the 'data' field. Depending on the data provided, the contract operations in essentially two modes: (1) Relaying signing policy. The structure of the calldata is: function signature (4 bytes) + active signing policy + 0 (1 byte) + new signing policy, total of exactly 4423 bytes. (2) Relaying signed message. The structure of the calldata is: function signature (4 bytes) + signing policy + signed message (38 bytes) + ECDSA signatures with indices (67 bytes each) This case splits into two subcases: - protocolMessageId = 1: Message id must be of the form (protocolMessageId, 0, 0, merkleRoot). The validity of the signatures of sufficient weight is checked and if successful, the merkleRoot from the message is returned (32 bytes) and the reward epoch id of the signing policy as well (additional 3 bytes) - protocolMessageId > 1: The validity of the signatures of sufficient weight is checked and if it is valid, the merkleRoot is published for protocolId and votingRoundId. Reverts if relaying is not successful.

```
function relay() external returns (    bytes);
```

### startingVotingRoundIds[​](#startingvotingroundids "Direct link to startingVotingRoundIds")

Returns the start voting round id for given reward epoch id.

```
function startingVotingRoundIds(    uint256 _rewardEpochId) external view returns (    uint256 _startingVotingRoundId);
```

#### Parameters[​](#parameters-6 "Direct link to Parameters")

-   `_rewardEpochId`: The reward epoch id.

#### Returns[​](#returns-5 "Direct link to Returns")

-   `_startingVotingRoundId`: The start voting round id.

### toSigningPolicyHash[​](#tosigningpolicyhash "Direct link to toSigningPolicyHash")

Returns the signing policy hash for given reward epoch id. The function is reverted if signingPolicySetter is set, hence on all deployments where the contract is used as a pure relay.

```
function toSigningPolicyHash(    uint256 _rewardEpochId) external view returns (    bytes32 _signingPolicyHash);
```

#### Parameters[​](#parameters-7 "Direct link to Parameters")

-   `_rewardEpochId`: The reward epoch id.

#### Returns[​](#returns-6 "Direct link to Returns")

-   `_signingPolicyHash`: The signing policy hash.

### verify[​](#verify "Direct link to verify")

Verifies the leaf (or intermediate node) with the Merkle proof against the Merkle root for given protocol id and voting round id. A fee may need to be paid. It is protocol specific. **NOTE:** Overpayment is not refunded.

```
function verify(    uint256 _protocolId,    uint256 _votingRoundId,    bytes32 _leaf,    bytes32[] _proof) external payable returns (    bool);
```

#### Parameters[​](#parameters-8 "Direct link to Parameters")

-   `_protocolId`: The protocol id.
-   `_votingRoundId`: The voting round id.
-   `_leaf`: The leaf (or intermediate node) to verify.
-   `_proof`: The Merkle proof.

#### Returns[​](#returns-7 "Direct link to Returns")

-   \`\`: True if the verification is successful.

### verifyCustomSignature[​](#verifycustomsignature "Direct link to verifyCustomSignature")

Checks the relay message for sufficient weight of signatures for the \_messageHash signed for protocol message Merkle root of the form (1, 0, 0, \_messageHash). If the check is successful, reward epoch id of the signing policy is returned. Otherwise the function reverts.

```
function verifyCustomSignature(    bytes _relayMessage,    bytes32 _messageHash) external returns (    uint256 _rewardEpochId);
```

#### Parameters[​](#parameters-9 "Direct link to Parameters")

-   `_relayMessage`: The relay message.
-   `_messageHash`: The hash of the message.

#### Returns[​](#returns-8 "Direct link to Returns")

-   `_rewardEpochId`: The reward epoch id of the signing policy.

## Events[​](#events "Direct link to Events")

### ProtocolMessageRelayed[​](#protocolmessagerelayed "Direct link to ProtocolMessageRelayed")

```
event ProtocolMessageRelayed(    uint8 protocolId,    uint32 votingRoundId,    bool isSecureRandom,    bytes32 merkleRoot)
```

### SigningPolicyInitialized[​](#signingpolicyinitialized "Direct link to SigningPolicyInitialized")

```
event SigningPolicyInitialized(    uint24 rewardEpochId,    uint32 startVotingRoundId,    uint16 threshold,    uint256 seed,    address[] voters,    uint16[] weights,    bytes signingPolicyBytes,    uint64 timestamp)
```

### SigningPolicyRelayed[​](#signingpolicyrelayed "Direct link to SigningPolicyRelayed")

```
event SigningPolicyRelayed(    uint256 rewardEpochId)
```

## Structures[​](#structures "Direct link to Structures")

### FeeConfig[​](#feeconfig "Direct link to FeeConfig")

```
struct FeeConfig {  uint8 protocolId;  uint256 feeInWei;}
```

### RelayGovernanceConfig[​](#relaygovernanceconfig "Direct link to RelayGovernanceConfig")

```
struct RelayGovernanceConfig {  bytes32 descriptionHash;  uint256 chainId;  struct IRelay.FeeConfig[] newFeeConfigs;}
```

### RelayInitialConfig[​](#relayinitialconfig "Direct link to RelayInitialConfig")

```
struct RelayInitialConfig {  uint32 initialRewardEpochId;  uint32 startingVotingRoundIdForInitialRewardEpochId;  bytes32 initialSigningPolicyHash;  uint8 randomNumberProtocolId;  uint32 firstVotingRoundStartTs;  uint8 votingEpochDurationSeconds;  uint32 firstRewardEpochStartVotingRoundId;  uint16 rewardEpochDurationInVotingEpochs;  uint16 thresholdIncreaseBIPS;  uint32 messageFinalizationWindowInRewardEpochs;  address payable feeCollectionAddress;  struct IRelay.FeeConfig[] feeConfigs;}
```